Which of the following describes denial as a defense mechanism?

Denial as a defense mechanism is characterized by a forceful refusal to accept painful emotions or difficult realities. When individuals engage in denial, they consciously or unconsciously reject or dismiss the existence of distressing thoughts, feelings, or situations. This mechanism can serve as a temporary respite from anxiety and emotional pain, allowing individuals to cope with feelings that may be overwhelming or intolerable.

In the context of the other options, while they describe various psychological responses, they do not encapsulate the essence of denial. For instance, acknowledging emotional pain but not understanding it deals more with awareness and processing rather than outright rejection of that pain. Intellectual justification involves rationalizing behaviors without acknowledging the underlying emotions, which differs from denying their existence entirely. Lastly, the inability to recall painful memories speaks to repression, another defense mechanism that involves suppressing distressing memories rather than outright denial, which is more about rejecting current emotional experiences. Thus, the correct answer reflects the core function of denial in psychological terms.